1. Field of the Invention
The present invention relates to a technique effective when applied to a communication system in an integrated network such as between a LAN and a telephone switching network.
2. Description of the Related Art
Recently, internet phone which is a LAN terminal provided with a voice communication function (hereinafter referred to as IT (internet phone) function) has begun to prevail. Control of intercommunication between such an internet phone and a telephone in a conventional switched circuit network is standardized by the gateway function provided for by ITU Recommendation H.323 protocol.
Such a terminal with an IT function connected with above-described LAN can carry out data communication of a plurality of applications as well as voice communication. More specifically, as far as the communication is between terminals with an IT function connected with a LAN, not only voice communication but also sharing an image of a word processor on a display and the like can be carried out. Such sharing of an image between terminals with an IT function can be materialized according to the recommendation with regard to data system/image system information transmission and reception provided for by ITU Recommendation H.323.
Conventionally, though advanced communication including data and voice communication can be carried out between terminals with an IT function on an LAN, when a terminal with an IT function communicates with a telephone connected with a common public transmission circuit network, the communication is limited to voice communication.
Therefore, even if a speaker on the side of a telephone owns a computer terminal capable of data communication, the speaker cannot enjoy functions of, for example, sharing image data between the computer terminal and a terminal with an IT function.
The present invention is made in view of the above, and an object of the present invention is to provide a technique which allows the enjoyment of an application service function on a LAN when a speaker on the side of a telephone carries out voice communication with a terminal with an IT function using the telephone (a public transmission circuit terminal).
According to one aspect of the present invention, in a circuit connecting unit which is connected with a telephone and a data terminal on one side and is connected with a LAN terminal with a speech unit via a LAN on the other side, a speech data interface for interfacing speech data between the telephone and the speech unit of the LAN terminal is provided, and a correlation table for correlating the telephone with the data terminal is provided. Further, a non-speech data interface for interfacing non-speech data between the data terminal and the LAN terminal is provided. In case data from the LAN terminal is speech data, the speech data is transmitted via the speech data interface to the telephone. In case data from the LAN terminal is non-speech data, the non-speech data is transmitted via the non-speech data interface to the data terminal.
In this way, in case the data is speech data, speech between the telephone and the LAN terminal via the speech data interface can be carried out. In case the data is non-speech data, data communication between the data terminal and the LAN terminal correlated with the telephone via the non-speech data interface can be carried out.
With this construction, the speaker on the side of the telephone can use an application function materialized between IT terminals using the data terminal correlated with the telephone as if the speaker were using a LAN terminal. For example, a speaker on the side of a telephone and an operator on the side of a LAN terminal can carry out work such as modification in graphic information or character information referring to the same word processor screen shared by the speaker and the operator.
According to another aspect of the present invention, in the circuit connecting unit mentioned in the above first aspect of the present invention, correlation between the identification number of the telephone and the identification number of the data terminal is used as the correlation table. More specifically, in case the circuit number assigned to the telephone is different from that assigned to the data terminal, by referring to the correlation table, circuit connection between the data terminal and the LAN terminal can be carried out.
According to still another aspect of the present invention, a control means for, in case data from the LAN terminal is speech data, transmitting the speech data via the speech data interface to the telephone, and in case data from the LAN terminal is non-speech data, transmitting the non-speech data via the non-speech data interface to the data terminal comprises an identification means for identifying a selection signal from the telephone. By identifying the selection signal using this identification means, either carrying out only voice communication with the speech unit of the LAN terminal or carrying out data communication also can be selected. Here, the selection signal may be a telephone i number followed by xe2x80x9c0#xe2x80x9d as a special number.